Abstract Signaling across biological membranes is critical to living cells and involves membrane- embedded receptors, which transduce extracellular stimuli into cytoplasmic responses through long-range allosteric communication. G protein-coupled receptors (GPCRs) constitute the largest family among these receptors. They are encoded by more than eight hundred genes in humans and are involved in a large diversity of critical functions but also diseases, making GPCRs the target of more than 40 % of current marketed drugs. Although a wealth of genomic and functional data is available on these receptors, the lack of high-resolution structural and mechanistic information hinders the development of specific therapies to modulate their function. The long-term goal of the proposed research is to develop novel integrated computational-experimental approaches and use these methods to uncover the sequence, structure and energetic relationships that govern GPCR interactions with extracellular ligands, intracellular proteins and GPCR signaling functions. We will address this problem using structure modeling, computational protein design, statistical analysis and experimental approaches. Specifically, we will develop novel computational techniques to model how a large diversity of regulatory molecules (ranging from solvent to lipids and peptides) binds to GPCRs even when no structural information is available on the molecules. We will also combine computational design and experimental approaches to uncover the allosteric determinants underlying GPCR signal transductions and use this knowledge to design GPCRs with reprogrammed signaling activities. Lastly, we will engineer novel GPCR/G protein signaling pairs to study the binding specificity determinants between receptors and effectors and to generate signaling switches that may prove useful for improving immune cell engineering in future immunotherapeutic applications. These studies, by advancing capabilities for predicting GPCR structures and their interactions with a wide diversity of molecules and for designing receptors modulating intracellular signaling pathways, will have high biomedical significance.